Significant advancements in the fields of chemistry and biotechnology have been made due to the use of microfluidic technology. The term “microfluidic” generally refers to a system or device having channels and chambers that are fabricated with a cross-sectional dimension (e.g. depth, width, or diameter) of less than a millimeter. The channels and chambers typically form fluid channel networks that allow the transportation, mixing, separation and detection of very small quantities of materials. Microfluidics are particularly advantageous because they make it possible to perform various chemical and biochemical reactions, macromolecular separations, and the like with small sample sizes, in automatable, high-throughput processes.
The microfluidic channel networks are fabricated in a working part, or substrate, that can be made from a variety of materials, including polymers, quartz, fused silica, or glass. In some commercially available microfluidic devices, the substrate is integrated into the microfluidic device by bonding it with a UV-cured adhesive to a body, or caddy, which may be constructed from materials such as acrylic or thermoplastic. Since substrates may be very small, the integration of the substrate into a relatively larger body of a microfluidic device often makes the substrate much easier to handle and more practical for performing microfluidic analyses.
Reservoirs or wells are typically included on the body and located so that they are in fluid communication with the channel networks of the substrate. The wells provide relatively larger access when compared to the microfluidic channels included in the channel networks of the substrate. The size of the wells makes it easier for a user to load samples or other materials into the channel networks.
One of the significant advantages of using microfluidic devices is that only minute quantities of fluids, or other materials in solution, are required making it possible to perform a very large number of assays with limited sample material. Microfluidic devices are particularly beneficial for DNA testing (e.g., for DNA separations) since DNA samples are typically gathered in relatively small quantities.
Because of the small channel size and fluid volumes used in microfluidic devices, there are factors that influence fluid flow within microfluidic devices that are less important in macro-scale flows. For example, within microfluidic channels physical properties of fluids such as surface tension, viscosity and electrical charges can have a much greater impact on fluid mechanics than those properties have in macro-scale flows. As a result, phenomena such as electrophoresis, which may be insignificant in macro-scale flows, may be used to manipulate fluids in the fluid networks of microfluidic devices.
In order for electrophoresis to take place, an electric field must be applied to the fluid in a microfluidic channel. One way to apply such an electric field is through electrodes contacting the fluid in the microchannel. For example, electric fields could be generated within the channels of a microfluidic device by inserting electrodes with different electric potentials into reservoirs on the body of the microfluidic device.
There is a need for a device that is able to accurately and consistently align electrodes with reservoirs on microfluidic devices. There is a further need that such a device be designed so that it can be integrated into automated, high-throughput processes.